1) Field of the Invention
The present invention relates to a technology for mobile object information management that manage identification information of mobile objects and enable efficiently searching information about a mobile object.
2) Description of the Related Art
Conventionally, traffic monitoring systems that read registration information on license plates of vehicles, are used in order to monitor traffic of vehicles such as automobiles. In the traffic monitoring systems, registration information on license plates photographed by image pickup devices are subject to a character recognition process, and its results as well as information about photographing locations and photographing time are stored in a database. As a result, information concerning the time and the locations, in which a vehicle with specific registration information runs, can be easily searched.
FIG. 14 illustrates installation of a roadside device of a conventional traffic monitoring system. An image pickup device 2 that photographs vehicles is installed on a pole 1 that supports a traffic signal. A recognizing device 3 that extracts license plate portions from the images and executes the character recognizing process on registration information is installed on the side of the pole 1.
The results of character recognition are transmitted to a server in a traffic-monitoring center via a network, and are stored into a database together with information about photographing location and photographing time. The database is used for applications such as searching certain time and location where a specific vehicle was present.
However, the roadside device of the traffic monitoring system shown in FIG. 14 is installed on a road in a fixed manner. Therefore, once the device is installed, it is not easy to move the device to a different location. Japanese Patent Application Laid-open No. 2003-22494 discloses a mobile object character recognizing system that can be transported by an automobile or the like, and the installation location of which, can be easily changed.
In the mobile object character recognizing system, to search a specific vehicle, registration information is input by a user in advance, and then it is determined whether the registration information matches with registration information obtained after character recognition. The search results are displayed.
However, if character recognition result of the registration information is inaccurate, the vehicle with the specific registration information is searched based on the inaccurate registration information.
The character recognition techniques currently available are not accurate enough. Consequently, as mentioned above, if there is an error in character recognition, a completely irrelevant vehicle is searched, thereby confusing the user.
A possible solution to this problem may be that the character recognition result for which the accuracy is not sufficiently high should not be taken into consideration. However, sometimes identification information of a vehicle, though not accurate enough, may prove useful. Therefore, an important object is to manage character recognition information in a balanced manner based on an extent of accuracy.